linux-kernel - [RFC][PATCH 26/36] objtool: mcount: Only keep ELF file size

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Message-ID: <3bc0af0d3ba3ab8f9582e4aaf54c85be9ebfbea5.1586468801.git.mhelsley@vmware.com>
Date:   Fri, 10 Apr 2020 12:35:49 -0700
From:   Matt Helsley <mhelsley@...are.com>
To:     <linux-kernel@...r.kernel.org>
CC:     Josh Poimboeuf <jpoimboe@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Julien Thierry <jthierry@...hat.com>,
        Ingo Molnar <mingo@...hat.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Miroslav Benes <mbenes@...e.cz>,
        Matt Helsley <mhelsley@...are.com>
Subject: [RFC][PATCH 26/36] objtool: mcount: Only keep ELF file size

Since we're no longer writing to the ELF file mapping and we're
not appending to it we don't need to keep more information from the
stat structure. At the same time we can give the smaller global
variable a better name.

Signed-off-by: Matt Helsley <mhelsley@...are.com>
---
 tools/objtool/recordmcount.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/objtool/recordmcount.c b/tools/objtool/recordmcount.c
index 95b93767d6eb..6de744aaf4c8 100644
--- a/tools/objtool/recordmcount.c
+++ b/tools/objtool/recordmcount.c
@@ -48,17 +48,17 @@
 static int fd_map;	/* File descriptor for file being modified. */
 static int mmap_failed; /* Boolean flag. */
 static char gpfx;	/* prefix for global symbol name (sometimes '_') */
-static struct stat sb;	/* Remember .st_size, etc. */
 static const char *altmcount;	/* alternate mcount symbol name */
 extern int warn_on_notrace_sect; /* warn when section has mcount not being recorded */
 static void *file_map;	/* pointer of the mapped file */
+static size_t file_map_size; /* original ELF file size */
 
 static struct elf *lf;
 
 static void mmap_cleanup(void)
 {
 	if (!mmap_failed)
-		munmap(file_map, sb.st_size);
+		munmap(file_map, file_map_size);
 	else
 		free(file_map);
 	file_map = NULL;
@@ -93,11 +93,13 @@ static void * umalloc(size_t size)
  */
 static void *mmap_file(char const *fname)
 {
+	struct stat sb;
+
 	/* Avoid problems if early cleanup() */
 	fd_map = -1;
 	mmap_failed = 1;
 	file_map = NULL;
-	sb.st_size = 0;
+	file_map_size = 0;
 
 	lf = elf_read(fname, O_RDWR);
 	if (!lf) {
@@ -129,6 +131,7 @@ static void *mmap_file(char const *fname)
 		}
 	} else
 		mmap_failed = 0;
+	file_map_size = sb.st_size;
 out:
 	fd_map = -1;
 
-- 
2.20.1